Mild Cognitive Impairment (MCI) is a subset of a broader clinical entity termed “Cognitive Impairment Non-Dementia”, or CIND.
There are many potential causes of CIND including: depression, alcohol/drug use, psychiatric disease, delirium, mental retardation, vascular causes, Parkinson's disease, epilepsy, multiple sclerosis, social factors, and sensory impairment.
MCI subjects are not demented, but are at risk of developing dementia such as Alzheimer's Disease (AD)(Larieu, S. et al. (2002) Incidence and outcome of mild cognitive impairment in a population-based prospective cohort. Neurology, 59: 1594-1599; Bennett, D. A. et al. (2002) Natural history of mild cognitive impairment in older persons. Neurology, 59: 198-205. In fact it has been estimated that 10% of those with MCI convert to AD (Bruscoli and Lovestone (2004), Is MCI really just early dementia? A systematic review of conversion studies. Int Psychogeriat. 16:2, 129-140).
MCI has been recognised by the FDA as a valid treatment target (FDA (2001), fda.gov/ohrms/dockets/ac/01/slides/3724s1—6_grundman/).
This has led to the emergence of a number of clinical trials for MCI (for example That et al., (2005), A randomized double-blind study of Rofecoxib in patients with Mild Cognitive Impairment, Neuropsychopharm, 30: 1204-1215).